With a 90-pound explosive charge attached to an iron spar protruding from her bow, the Confederate sub H. L. Hunley looked like a lopsided hypodermic needle. On the night of February 17, 1864, off Charleston, South Carolina, she gave the Union sloop Housatonic a lethal injection. After ramming the barbed spar into the Housatonic’s wooden hull, crewmen furiously hand-cranked their engineless vessel across the surface of the harbor amid small-arms fire from the surprised Yankee sailors. In so doing, they unspooled a line attached to a trigger mechanism. About a minute later, a mighty explosion sank the Housatonic almost instantly, killing five of her crew. According to one account, the Hunley signaled with a gas lantern to lookouts four miles away on Sullivans Island and then disappeared with her crew of nine.

Since then, the Hunley has been awash in mystery and controversy as well as mud. The controversy intensified after she was lifted from the harbor floor on August 8, 2000, by a team led by the novelist and shipwreck expert Clive Cusler. Another salvor says he found the submarine back in 1970 (although he made no attempt to raise her), while a self-styled “degreed archeologist” says he located her in 1973. But Cussler insists his group was the first to pinpoint the Hunley ’s location, on May 4, 1995, after a 15-year search. The government agrees with his claim.

The Hunley Commission, a semiprivate organization operated by South Carolina, has taken charge of the submarine’s preservation. At the new Warren Lasch Conservation Center in North Charleston, the Hunley rests submerged in a huge water tank whose pH, oxygen level, and conductivity are regulated by a computer. The vessel turns out to be rounder than was thought. She also has previously unrecorded hydrodynamic fins built into her sides, and there are signs that gunshots from the Housatonic may have penetrated her conning tower. Nothing as yet explains, however, what made her sink.

Robert Neyland, the project director, and his team are using a three-dimensional scanner to record 2.5 billion survey points, which will map the artifact’s external shape. Sonar allows the researchers to probe its interior. “We plan to remove rivets and take off plates shortly,” says Neyland, “and we plan to go inside by March.” What does he expect to find? “You never know for sure, but I think we’ll find human remains.”

—Fred L. Schultz